/**
package ch5;

public class Zxf9{
    public static void main(String[] args) {
        int a=1;
        int b=0;
        while (a<=1000){
            b=b+a;
            a++;
        }
        System.out.println("总和："+b);
    }
}
*/
package ch5;

public class Zxf9{
    public static void main(String[] args) {
        int a=1;
        double b=1;
        while (a<=20){
            b=a*b;
            a++;
        }
        System.out.println("乘积："+b);
    }
}